Screw turbine



J. AKINS SCREW TURBINE Filed May 27, 1942 Nov. 16, 1943. l

@UIMM Patented Nov. 16, 1943 Y SCREW TURBINE Jake Akins, 'StatesbormGauassignor `of one-half l toAlfred A. Dorman, Statesboro', Ga.

Application May 27, 1942, Serial No. 444,727

6 Claims.v (C1. 2537-31) Thisinventin relates toturbinesvof the axialflow, screw rotor type, and anfobject'of` the same y is to provide aturbine unit which maybe quickly Iand. easily installed inv variouslocations and under varying conditions, and which will deliver highpower output per size of unit.

Another object of the invention is to provide ya lturbine ofthe typespeciedutilizing a stator casing andcoacting rotor screW of taperedcontour` from `the inlet to the outlet ends thereof, the propeller beingnon-displaceably mounted in the casing Aand the unit as a whole beingcompact and capableof delivering maximum powerV for its size. t

"A vfurther object of the invention is to vprovide a turbine of theaxial-flow type wherein there is a minimum of slippagev or loss betweenIthe stator and rotor and wherein the efficiency per'volume orhead-pressure of water is relatively high.

The foregoing and other objects and advantages `will become apparent inview of the foregoing description taken in conjunction with the drawing,wherein:

Fig. 1 is a substantially y central longitudinal section of a turbine inaccordance with the invention;

Fig. 2, an end elevation taken substantially on the line 2--2, Fig. 1;and, v

Fig. 3, an enlarged fragmentary section of the turbine screw or rotor.

Referring to the drawing in detail, the turbine assembly or unitcomprises a stator in the form of a casing, generally indicated at I0,which is of tapered contour from the enlarged inlet to the reducedoutlet end thereof. This casing may be made of non-corrosive sheetmetal, composition or cementitious material or the like or it may be abronze casting. However, it is preferred to utilize a stator casingwhich may be transported from point to point as desired.

Within the casing a turbine roto-r of the screw type is mounted and isgenerally indicated at II, the rotor comprising a shaft I2 havingthereon a spiral blade or vane I3. While the blade is shown in Fig. 3 asbeing c-ast integrally with the shaft I2, it will be understood that itmay be made of relatively thin gauge metal and rolled, extruded orotherwise suitably formed and then secured as by welding to the shaft.

The spiral vane or blade I3 follows the tapered contour of the casingrI0, and the outer edge-of the blade is formed with a flange I4 whichprojects forwardly or towards the inlet lend of the casing. This flangeI4 provides in conjunction with the active or working face I3' of theblade a generally dishes construction; while atrae `Vsame time theflange lies Arelatively 4close tothe inner surface of the casing andreduces the slippage or leakage loss at thispcint.v The flange ispreferably -of relatively wide dimensions and has its forward or leadingedge tapered inwardly, as at I5, toward the active face I3' of theblade, thereby further reducing the tendency towards slippage or leakagebetween the flange and the casing. l

The shaft I2 withV its-blade orvan'e I3 is preferably rigidlymounted tothe lcasing I0, and accordingly, bearing brackets 'or members I6 and I'lare fixed tothe casing at the inlet and outlet ends thereof Sand are'provided with bearings I8 and ,I9f for the `opposite ends of the shaftI2.

The brackets I6 and II4 may be made of suitable non-corrosive materialand should b'e sufficiently rugged to withstand the pressures to whichthe unit maybe subjected and at the Sametime prevent any relativedisplacement between the rotor and its casing.

f The front end of the casing is preferably turned outwardly orotherwise suitably provided with a mounting flange 20 formed with aplurality of bolt holes 2|, and connected to this flange is a 'draftcasing or tube 22, which may be attached to and form part of the unit,or it may be installed prior to installation of the unit.

The rear end of the shaft I2 is provided with a worm 23 adapted to meshwith a worm gear 24 mounted on a drive shaft 25, said shaft extending tothemember to be driven.

In operation, the turbine mas7 be disposed either vertically,horizontally or at various angles between thev vertical and horizontal,and may be conveniently located in a draft tube, a runway at the base ofadam, in the bed of a stream. or wherever` suitable head pressure isavailable. The water entering the casing Il) at the forward or enlargedend thereof engages the active face of the vane or blade I3 and causesrotation of the shaft I2. Due to the anged and generally dishedconstruction of the blade I3, maximum efficiencyy is obtained, therebeing reduced slippage or leakage between the blade and casing. Actualexperience has demonstrated that considerable power may be madeavailable with relatively low head pressure, such as where only smallstreams or brooks can be used for obtaining such pressure. The unit maybe easily and `quickly installed and may be readily transported fromplace to place Wherever it can be advantageously utilized. l

It will be understood that certain limited changes in construction anddesign of the improved turbine may be adopted without departing from thespirit or scope of the invention as defined by the appended claims.

What is claimed is:

1. A turbine comprising ya stator casing of taper contour from its inletto its outlet ends an a rotor mounted in said turbine and comprising ashaft havin-g a spiral blade or vane thereon which follows the taper ofthe.casing, said blade being formed with a flange on the outer edgethereof extending towards the inlet end of the casing.

2. A turbine comprising an elongated stator of tapered contour fromvits-enlarged inlet Ato its reduced outlet end and a rotor mounted insaidcasing and comprising arshaft having a spiral blade thereon whichfollows the tapered con'- tour of the casing, the outer edge of theblade being formed with a forwardly extending flange which provides inconjunction with the active face of the blade a generally dishedconstruction, there being a'minimum -ofclearance between the flange andthe inner surface ofthe casing, and means rigidly connecting the saidshaft to thevcasing. "l

4. A turbinel comprising an elongated `casing of tapered contour fromits enlarged inlet end to its reduced outlet end land a 4rotor -inountedin said casing and comprising aV shaft having a spiral blade thereonformed withl an extended flange -on the outer edge thereof whichprojects towards the inlet end of the casing, there beinga minimum ofclearance between said flange and the adjacent inner surface of thecasing, and

.bearing brackets rigidly connecting the opposite inlet end of thecasing and lies in a plane substantially coincident with the adjacentinnersur- 1 :face of the casing, there being a minimum of clearanceybetween said flange and the said inner surface Aof .the casing, andmeans rigidly connecting the opposite ends of the shaft to the casingand holdingthe rotor-and casing togetherv as a non-fdisplaceable unit. Yv y 6. A turbine comprising an elongated casing or tapered contour fromits inlet to its outlet end,

thevlarger end of the casing constituting the inlet end, and the'smallerend thereof constituting the discharge end, a rotor mounted-in saidcasing and comprising a shaft having a spiral blade formed jthereon,lthe outer edge portion" of said blade being'formed-with an. extendedflange whichprojects toward the inlet end of the casing, thevbody ofsaid blade extending ina planegsubstantially normal to the longitudinalaxis of the casing and-saidange extendingvin a plane substantiallycoincident lwith thevadja- LJAKE AKiNs.

